Spectroscopic and X-ray crystallographic studies of pentameric ethyl cyclopolyphosphine derivatives of triosmium carbonyl clusters

Reaction of pentaethylcyclophosphine, (EtP)(5), with triosmium cluster [Os-3(CO)(10)(NCMe)(2)] in dichloromethane at room temperature afforded [Os-3(CO)(10){1,2-(EtP)(5)}] (1) with an unusual 1,2-chelation mode for the cyclophosphine. The same reactants at a higher temperature gave rise to [Os-3(CO)(10){1,3-(EtP)(5)}] (2). Treatment of the same ligand with triosmium cluster [Os-3(CO)(11)(NCMe)] yielded several new clusters [Os-3(CO)(11)(EtP)(5)}] (3), [{Os-3(CO)(11)}(2){1,3-(EtP)(5)}] (4), [{Os-3(CO)(11)}(2){1,,2-(EtP)(5)}] (5), [Os-3(CO)(10){1,2,3-(EtP)(5)}Os-3(CO)(11)] (6) and [Os-3(CO)(10){1,2,4-(EtP)(5)}Os-3(CO)(11)] (7).